1. Field of the Invention
The present invention relates to a vibration reduction control method and apparatus of a power train by controlling a motor torque of a vehicle, and particularly to a method and apparatus for reducing vibrations occurring in a power train when driving on a protruded portion of a road surface by using a motor torque control.
2. Description of Related Art
Gasoline engines and diesel engines both use fossil fuel and may be disadvantageous due to causing environment contamination from exhaust gas. This environment contamination may be considered a global warming phenomenon due to carbon dioxide and may contribute a respiratory system-related disease due to the ozone generation. A risk of fossil fuel depletion may exists due to the substantially small amount of fossil fuel on the earth.
To attempt to overcome the above mentioned problems, there exist several alternatives to fossil fuel such as an electric vehicle (EV) driven by driving a driving motor, a hybrid electric vehicle (HEV) driven by an engine and a driving motor, and a fuel cell electric vehicle (FCEV) driven by a driving motor with the electric power generated from a fuel cell.
In addition to the above mentioned driving motor, the electric vehicle may comprise a battery as a power charging means which supplies electric power to a driving motor and an inverter for rotating the driving motor. In the fuel battery cell vehicle, a power charging means such as a battery, etc. may be adapted as a sub-driving force source connected in parallel with a fuel cell, a main driving force source. In recent years, a fuel cell hybrid system with a super capacitor functioning as a sub-driving force source in addition to a battery has been developed and is currently in use. Thus, the electric power from a power charging means (or fuel cell) is phase-converted in accordance with a control signal from an inverter controller for driving a driving motor.
Meanwhile, many vibrations occur due to impacts to an electric vehicle on protruded portions of a road surface. Furthermore, the vibrations may be transferred to a vehicle body and a power train via suspensions and may then be transferred to the passengers in the vehicle through the seats and the steering wheel, thus causing unsteadiness. The vibrations generated due to impacts affect a suspension inherent mode and a power train inherent mode; however since the vibrations are transferred from the power trains, it may be difficult to reduce such vibrations due to increased inertia force of the power train.
A rubber mount bush may be disposed on a mount. The mount may be a connection member in mounting a power train in an engine room to prevent the transfer of vibrations. Alternatively, a hydro mount bush may be used, which uses fluid to prevent the transfer of vibrations. In other words, vibration reduction has been attempted using the cushioning effects of rubber and fluid.
The above mentioned method, which may be called a passive method, is directed to preventing the vibrations from being transferred to the indoor space of the vehicle by using a cushioning material as an insulation material for vibrations. The hydro mount bush is generally used in high end vehicles due to high manufacturing costs and the space needed for installation of the mount bush.